https://zenodo.org/record/1258475/files/article.pdf

Electron transfers in chemistry and biology

Detection of chemical and biological agents plays a fundamental role in biomedical, forensic and environmental sciences1–4 as well as in anti bioterrorism applications.5–7 The development of highly sensitive, cost effective, miniature sensors is therefore in high demand which requires advanced technology coupled with fundamental knowledge in chemistry, biology and material sciences.8–13

In general, sensors feature two functional components: a recognition element to provide selective/specific binding with the target analytes and a transducer component for signaling the binding event. An efficient sensor relies heavily on these two essential components for the recognition process in terms of response time, signal to noise (S/N) ratio, selectivity and limits of detection (LOD).14,15 Therefore, designing sensors with higher efficacy depends on the development of novel materials to improve both the recognition and transduction processes. Nanomaterials feature unique physicochemical properties that can be of great utility in creating new recognition and transduction processes for chemical and biological sensors15–27 as well as improving the S/N ratio by miniaturization of the sensor elements.28

Gold nanoparticles (AuNPs) possess distinct physical and chemical attributes that make them excellent scaffolds for the fabrication of novel chemical and biological sensors (Figure 1).29–36 First, AuNPs can be synthesized in a straightforward manner and can be made highly stable. Second, they possess unique optoelectronic properties. Third, they provide high surface-to-volume ratio with excellent biocompatibility using appropriate ligands.30 Fourth, these properties of AuNPs can be readily tuned varying their size, shape and the surrounding chemical environment. For example, the binding event between recognition element and the analyte can alter physicochemical properties of transducer AuNPs, such as plasmon resonance absorption, conductivity, redox behavior, etc. that in turn can generate a detectable response signal. Finally, AuNPs offer a suitable platform for multi-functionalization with a wide range of organic or biological ligands for the selective binding and detection of small molecules and biological targets.30–32,36 Each of these attributes of AuNPs has allowed researchers to develop novel sensing strategies with improved sensitivity, stability and selectivity. In the last decade of research, the advent of AuNP as a sensory element provided us a broad spectrum of innovative approaches for the detection of metal ions, small molecules, proteins, nucleic acids, malignant cells, etc. in a rapid and efficient manner.37



Figure 1

Physical properties of AuNPs and schematic illustration of an AuNP-based detection system.



In this current review, we have highlighted the several synthetic routes and properties of AuNPs that make them excellent probes for different sensing strategies. Furthermore, we will discuss various sensing strategies and major advances in the last two decades of research utilizing AuNPs in the detection of variety of target analytes including metal ions, organic molecules, proteins, nucleic acids, and microorganisms.

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Gold nanoparticles in chemical and biological sensing.

The science of the total environment

Recent developments in polysaccharide-based materials used as adsorbents in wastewater treatment

Direct And Mediated Anodic Oxidation of Organic Pollutants

The use of a closed-loop on-line enrichment procedure in combination with an ICP plasma emission spectrometer has been developed for the analysis of trace metal ions, such as Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. The procedure utilizes a preconcentration column filled with an anion exchange resin and 8-hydroxy-7-iodoquinoline-5-sulphonic acid is added to the sample prior to preconcentration. Details on the optimization of pretreatment and instrumental conditions are described. Results obtained for the analysis of river water and antarctic seawater are reported.

On-line preconcentration and ICP determination for trace metal analysis

Marine sediments are sinks and repositories of matter recirculated in the environment by a number of different processes. They behave as environmental archives, providing a key to the understanding of the processes occurring in a given region in the course of time. In this work, we characterized the inorganic composition of a surface sediment core collected in the polynya of Terra Nova Bay (TNB) in the Ross Sea, an area of major environmental interest as it hosts a number of crucial processes connecting atmospheric transport with the Southern Ocean system. The total concentrations of major, minor, and trace elements were determined. The results were treated with chemometric techniques. In order to investigate the environmental mobility of several elements, the modified Bureau of Community Reference (BCR) three-step sequential extraction procedure was applied and the partitioning of eight metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) into different fractions was determined. The knowledge of the metal distrib...

Temporal variability and environmental availability of inorganic constituents in an Antarctic marine sediment core from a polynya area in the Ross Sea

The Oxidation of Aromatic Ortho-diols by Periodic Acid. Kinetics and Mechanism

Ion chromatography and fluorescence detection of trace metal ions

FeIII reacts with mercaptocarboxylic acids (HORSH), such as 2-mercaptoethanoic acid, 2-mercaptopropanoic acid, 2-mercapto-1,4-butanedioic acid and penicillamine (2-amino3-methyl-3-mercaptobutanoic acid) to give, in perchloric acid medium, 1∶1 complexes, Fe3++HORSH⇄Fe(OSR)++ 2H+. These complexes then undergo redox decomposition to give a disulphide dimer: 2Fe(OSR)++2H+⇄2Fe2++ HOR-S- S- ROH. The present study reports equilibrium data on the stability of the intermediate complexes, and kinetic data for the fast complex formation, as well as for the slower redox decomposition.

Edoardo Mentasti

Papers

On-line preconcentration and ICP determination for trace metal analysis

Temporal variability and environmental availability of inorganic constituents in an Antarctic marine sediment core from a polynya area in the Ross Sea

The Oxidation of Aromatic Ortho-diols by Periodic Acid. Kinetics and Mechanism

Ion chromatography and fluorescence detection of trace metal ions

Kinetics and mechanisms of complex formation and redox reactions of iron(III) with mercaptocarboxylic ligands in acid perchlorate media